geom_multi_raster {plothelper}

Geom Layer for Drawing Multiple Rasters

Description

Unlike annotation_raster which draws only 1 raster, this layer draws one or more rasters at the same time. The data must be a tbl object created by package tibble and the reason is that, as we must give each rectangle a vector of colors, the column that contains these vectors of colors must be a list rather than a vector. A list can be a column for tbl object, not for a normal data frame. See examples. Accepted properties are:

• (1) xmin.

• (2) xmax.

• (3) ymin.

• (4) ymax.

• (5) raster. a list with 1 or more rasters. If you have only 1 raster, you also have to put it into a list. Each raster should be a matrix, a raster object, a character vector or a magick object read into R by magick::image_read. You can also use a data frame created by package tibble to combine xmin, xmax, ymin, ymax, raster.

• (6) interpolate. It is the same as that in annotation_raster except that the default value is TRUE. It can be used either inside or outside the aes(...) function. Its length must be either 1 or the same as the number of rasters.

• (7) flip. The default is FALSE. You only need to use TRUE when you use coord_flip. Used outside the aes(...) function.

Usage

geom_multi_raster(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  position = "identity",
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  flip = FALSE,
  ...
)

Arguments

mapping

aes mapping.

data

data. It should be a tbl object.

stat

stat.

position

position.

na.rm

logical, whether to remove NA values.

show.legend

This will not be used because the layer does not create any legend.

inherit.aes

logical, whether to inherit aes from ggplot().

flip

see description.

...

additional parameters.

Examples

# Example 1: use vectors and a list. 
mycolor=list(
	c1=matrix(c("red", "blue", "green", "yellow"), nrow=2), 
	c2=matrix(c("green", "yellow")), 
	c3=matrix(c("purple", "red")))
xmin=1: 3
xmax=(1: 3)+0.8 
ymin=c(0, 1, 2)
ymax=c(1, 3, 5)
ggplot()+
	geom_multi_raster(aes(xmin=xmin, xmax=xmax, 
	ymin=ymin, ymax=ymax, raster=mycolor))
#
# Example 2: the same as example 1
# except flip=TRUE.
ggplot()+coord_flip()+
	geom_multi_raster(aes(xmin=xmin, xmax=xmax, 
	ymin=ymin, ymax=ymax, raster=mycolor), flip=TRUE)